access to a vm_page. It is basically an atomically accessed thread ID field
in the vm_page structure, which is explicitly set by macros marking the
critical sections. As a first positive effect I had to review quite a bit of
code and found several issues.
* Added several TODOs and comments. Some harmless ones, but also a few
troublesome ones in vm.cpp regarding page unmapping.
* file_cache: PrecacheIO::Prepare()/read_into_cache: Removed superfluous
vm_page_allocate_page() return value checks. It cannot fail anymore.
* Removed the heavily contended "pages" lock. We use different policies now:
- sModifiedTemporaryPages is accessed atomically.
- sPageDeficitLock and sFreePageCondition are protected by a new mutex.
- The page queues have individual locks (mutexes).
- Renamed set_page_state_nolock() to set_page_state(). Unless the caller says
otherwise, it does now lock the affected pages queues itself. Also changed
the return value to void -- we panic() anyway.
* set_page_state(): Add free/clear pages to the beginning of their respective
queues as this is more cache-friendly.
* Pages with the states PAGE_STATE_WIRED or PAGE_STATE_UNUSED are no longer
in any queue. They were in the "active" queue, but there's no good reason
to have them there. In case we decide to let the page daemon work the queues
(like FreeBSD) they would just be in the way.
* Pulled the common part of vm_page_allocate_page_run[_no_base]() into a helper
function. Also fixed a bug I introduced previously: The functions must not
vm_page_unreserve_pages() on success, since they remove the pages from the
free/clear queue without decrementing sUnreservedFreePages.
* vm_page_set_state(): Changed return type to void. The function cannot really
fail and no-one was checking it anyway.
* vm_page_free(), vm_page_set_state(): Added assertion: The page must not be
free/clear before. This is implied by the policy that no-one is allowed to
access free/clear pages without holding the respective queue's lock, which is
not the case at this point. This found the bug fixed in r34912.
* vm_page_requeue(): Added general assertions. panic() when requeuing of
free/clear pages is requested. Same reason as above.
* vm_clone_area(), B_FULL_LOCK case: Don't map busy pages. The implementation is
still not correct, though.
My usual -j8 Haiku build test runs another 10% faster, now. The total kernel
time drops about 18%. As hoped the new locks have only a fraction of the old
"pages" lock contention. Other locks lead the "most wanted list" now.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34933 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Added VMCache::MovePage() and MoveAllPages() to move pages between caches.
* VMAnonymousCache:
- _MergeSwapPages(): Avoid doing anything, if neither cache has swapped out
pages.
- _MergeSwapPages() does now also remove source cache pages that are
shadowed by consumer swap pages. This allows us to call _MergeSwapPages()
before _MergePagesSmallerSource(), save the swap page shadowing check
there and get rid of the vm_page::merge_swap flag. This is an
optimization based on the assumption that usually none or only few pages
are swapped out, so we save a lot of checks.
- Implemented _MergePagesSmallerConsumer() as an alternative to
_MergePagesSmallerSource(). The former is used when the source cache has
more pages than the consumer cache. It iterates over the consumer cache's
pages, moves them to the source and finally moves all pages back to the
consumer. The final move is relatively cheap (though unfortunately we
still have to update all pages' vm_page::cache field), so that overall we
save iterations of the main loop with the more expensive checks.
The optimizations particularly improve the common fork()+exec*() situations.
fork() uses CoW, which is implemented by putting two new empty caches between
the to be copied area and its cache. exec*() destroys one copy of the area,
its cache and thus causes merging of the other new cache with the old cache.
Since this usually happens in a very short time, the old cache does still
contain many pages and the new cache only few. Previously the many pages were
all checked and moved individually. Now we do that for the few pages instead.
A very extreme example of this situation is the Haiku image build. jam has a
huge heap (> 200 MB) and it fork()s+exec*()s for every action to be executed.
Since during the cache merging the cache is locked, any write access to a
heap page causes jam to block until the cache merging is done. Formerly that
took so long that it killed a lot of parallelism in multi-job builds. That
could be observed particularly well when lots of small actions where executed
(like the Link, XRes, Mimeset, SetType, SetVersion combos when building
executables/libraries/add-ons). Those look dramatically better now.
The overall speed improvement for a -j8 image build on my machine is only
about 15%, though.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34784 a95241bf-73f2-0310-859d-f6bbb57e9c96
- Replaced the "userOnly" parameter by a "flags" parameter, that allows to
specify kernel and userland stack traces individually.
- x86, m68k: Don't always skip the first frame as that prevents the caller
from being able to record its own address.
* capture_tracing_stack_trace(): Replaced the "userOnly" parameter by
"kernelOnly", since one is probably always interested in the kernel stack
trace, but might not want the userland stack trace.
* Added stack trace support for VM cache kernel tracing.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34742 a95241bf-73f2-0310-859d-f6bbb57e9c96
* When DEBUG_SPINLOCK_LATENCIES is 1, the system will panic if any spinlock is
held longer than DEBUG_LATENCY micro seconds (currently 200). If your system
doesn't boot anymore, a new safemode setting can disable the panic.
* Besides some problems during boot when the MTRRs are set up, 200 usecs work
fine here if all debug output is turned off (the output stuff is definitely
problematic, though I don't have a good idea on how to improve upon it a lot).
* Renamed the formerly BeOS compatible safemode settings to look better; there
is no need to be compatible there.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33953 a95241bf-73f2-0310-859d-f6bbb57e9c96
(hopefully) correct place.
* It seems to be even harder to understand basic locking primitives: when you
think about it, it shouldn't surprise you that conditional variables never
return B_WOULD_BLOCK. This fixes gdb again.
* Added tracing support to the ports subsystem.
* get_port_message() will now resize the port heap if needed (but will also
take timeouts into account while doing so, more or less). The initial port
space is 4MB (as before), the growth rate is the same, and the system wide
limit is arbitrarily set to 64 MB (all swappable). A team limit has been set
to 8 MB, but is not enforced yet. Since ports are using up address space in
the kernel, those seems to be proper limits.
* This also fixes a strange, and rare lockup where the mouse cursor would still
move, but everything else would basically hang, but look perfectly normal from
KDL on the first look. As recently happened on Brecht's laptop, and debugged
by mmlr and me: the cbuf space got used up when lots of windows wanted to
redraw after a workspace switch. The app_server wouldn't answer anymore to
client requests, but thought it would have done so, as LinkSender::Flush()
doesn't care if it got a B_NO_MEMORY (the ports will now block until memory
is available if possible, so that should not be a problem anymore).
* Improved "port" KDL command, it now also prints the messages in the port.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33735 a95241bf-73f2-0310-859d-f6bbb57e9c96
now be inspected. Still work in progress -- bit fields and arrays don't work
correctly yet nor does type lookup beyond the current compilation unit.
* Made most of the debugger output configurable via a config header. By default
it's much less noisy now.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33217 a95241bf-73f2-0310-859d-f6bbb57e9c96
have a simple dedicated heap for the kernel debugger with stacked allocation
pools (deleting a pool frees all memory allocated in it). The heap should
eventually be used for all commands that need temporary storage too large for
the stack instead of each using its own static buffer.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30949 a95241bf-73f2-0310-859d-f6bbb57e9c96
enter/exit code. There's no real reason not to keep kernel breakpoints
enabled when in userland (unless there are breakpoints installed for the
team, of course).
* Enabled kernel breakpoints by default (check your kernel_debug_config.h,
if you have overridden it!), since they don't really add any overhead
anymore.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30206 a95241bf-73f2-0310-859d-f6bbb57e9c96
* vm_clone_area() does now set the B_SHARED_AREA flag on both the source
and the cloned area. This is necessary, since it would no longer be
guaranteed that areas are backed by leaf caches only (after
fork()ing), which doesn't work with our cache merging strategy.
Fixes#2605.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28296 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Turned the checks for all those macros to "#if"s instead of "#ifdef"s.
* Introduced macro KDEBUG_LEVEL which serves as a master setting.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28248 a95241bf-73f2-0310-859d-f6bbb57e9c96
Currently it only contains KDEBUG and the block cache debugging macros.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27816 a95241bf-73f2-0310-859d-f6bbb57e9c96
* {read,write}_pages() use vfs_{read,write}_pages() now, instead of
invoking the FS {read,write}_pages() hooks.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26750 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Cleanup the license header and add authors
* Sort the available keymaps list in the config file and add 'dv'
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25806 a95241bf-73f2-0310-859d-f6bbb57e9c96
keymap there too.
* Add a config header where one can select what KDL keymap should be used
(currently only 'us' and 'sg' are available though).
* Provide a third keymap that is used when the alt modifier is used (the swiss
german keymap is pretty useless without alt as all the useful keys like
backslash and curly braces use alt).
Our KDL is so powerful and nice to use, the only thing that bothered me was
that I always had to think about where some of the special keys are located in
the US keymap. So this simple compile-time keymap switching provided to be
helpful for me and might be for others too. Keymaps for other layouts obviously
have to be written before this becomes really useful.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25803 a95241bf-73f2-0310-859d-f6bbb57e9c96
compatible with what our code assumed (pointers to objects of
TraceEntry and its POD base class trace_entry aren't identical
anymore).
* Added optional stack traces for ktrace_printf() output in the kernel.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25531 a95241bf-73f2-0310-859d-f6bbb57e9c96
- Prepend "ahci port" to all trace entries in ahci_port.cpp.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25293 a95241bf-73f2-0310-859d-f6bbb57e9c96
- Added controller attribute to the AHCIPort class for debugging purposes.
AHCI is failing whenever the PRD table has an address above the 2048 Mb mark.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25291 a95241bf-73f2-0310-859d-f6bbb57e9c96
block would be incorrectly addressed when allocating a stream - this could
cause random blocks to be overwritten, and therefore could cause many sorts
of problems.
* Moved BFS_TRACING macro to the tracing_config.h file, and let it follow the
new semantics of those other macros in there.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25249 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Introduced the TCP_TRACING macro in tracing_config.h.
* Enlarged the default trace size to something a tiny bit useful (but still
acceptable for systems with little RAM).
* Cleanup.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25235 a95241bf-73f2-0310-859d-f6bbb57e9c96
* cache paranoia was always enabled.
* Changed from paranoia on/off to levels. Adjusted the macros to take a
level argument.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25215 a95241bf-73f2-0310-859d-f6bbb57e9c96
defined/undefined to numeric values (0 for undefined). This allows for
trace levels.
* Set SYSCALL_TRACING_IGNORE_KTRACE_OUTPUT default to 1, since this is
what one usually wants.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25213 a95241bf-73f2-0310-859d-f6bbb57e9c96
* Added "mode" parameter to set_paranoia_check(), which specifies
whether the check is supposed to already exist/not exist yet. This
allows for, as it turns out, very useful additional tests. Added
{ADD,UPDATE}_PARANOIA_CHECK macros that imply the used "mode"
parameter.
* PARANOIA_SLOT_COUNT was accidentally redefined in the source file.
* Fixed remove_paranoia_check(). It didn't remove anything.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25207 a95241bf-73f2-0310-859d-f6bbb57e9c96
We're a bit limited since that increases the kernel size the boot loader
needs to reserve. We should probably make that configurable as well.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25206 a95241bf-73f2-0310-859d-f6bbb57e9c96
setting to force BLockers to be semaphore style. This may help with
debugging deadlocks.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25096 a95241bf-73f2-0310-859d-f6bbb57e9c96
Ingo Weinhold